Actually fix the rare execution error this time

src/diff/type.jl

@@ -5,7 +5,7 @@ A named tuple representing a difference of added and removed nodes and edges on
 """
 const Diff = NamedTuple{
     (:addedNodes, :removedNodes, :addedEdges, :removedEdges, :updatedChildren),
-    Tuple{Vector{Node}, Vector{Node}, Vector{Edge}, Vector{Edge}, Vector{Tuple{Node, Symbol, Symbol}}},
+    Tuple{Vector{Node}, Vector{Node}, Vector{Edge}, Vector{Edge}, Vector{Tuple{Node, AbstractTask}}},
 }
 
 function Diff()
@@ -15,7 +15,7 @@ function Diff()
         addedEdges = Vector{Edge}(),
         removedEdges = Vector{Edge}(),
 
-        # children were updated from updatedChildren[2] to updatedChildren[3] in node updatedChildren[1]
-        updatedChildren = Vector{Tuple{Node, Symbol, Symbol}}(),
+        # children were updated in the task, updatedChildren[x][2] is the task before the update
+        updatedChildren = Vector{Tuple{Node, AbstractTask}}(),
     )::Diff
 end

src/graph/mute.jl

@@ -189,6 +189,8 @@ function update_child!(graph::DAG, n::Node, child_before::Symbol, child_after::S
         return nothing
     end
 
+    taskBefore = copy(n.task)
+
     if !((child_before in n.task.t1_inputs) || (child_before in n.task.t2_inputs))
         println("------------------ Nothing to replace!! ------------------")
         child_ids = Vector{String}()
@@ -213,7 +215,7 @@ function update_child!(graph::DAG, n::Node, child_before::Symbol, child_after::S
 
     # keep track
     if (track)
-        push!(graph.diff.updatedChildren, (n, child_before, child_after))
+        push!(graph.diff.updatedChildren, (n, taskBefore))
     end
 end
 

src/operation/apply.jl

@@ -132,11 +132,11 @@ function revert_diff!(graph::DAG, diff::Diff)
         insert_edge!(graph, edge.edge[1], edge.edge[2], track = false)
     end
 
-    for (node, before, after) in diff.updatedChildren
+    for (node, task) in diff.updatedChildren
         # node must be fused compute task at this point
         @assert typeof(node.task) <: FusedComputeTask
 
-        update_child!(graph, node, after, before, track = false)
+        node.task = task
     end
 
     graph.properties -= GraphProperties(diff)
@@ -234,6 +234,7 @@ function node_reduction!(graph::DAG, nodes::Vector{Node})
 
     # set of the new parents of n1
     newParents = Set{Node}()
+
     # names of the previous children that n1 now replaces per parent
     newParentsChildNames = Dict{Node, Symbol}()
 
@@ -255,12 +256,14 @@ function node_reduction!(graph::DAG, nodes::Vector{Node})
         remove_node!(graph, n)
     end
 
-    setdiff!(newParents, n1Parents)
-
     for parent in newParents
         # now add parents of all input nodes to n1 without duplicates
-        insert_edge!(graph, n1, parent)
+        if !(parent in n1Parents)
+            # don't double insert edges
+            insert_edge!(graph, n1, parent)
+        end
 
+        # this has to be done for all parents, even the ones of n1 because they can be duplicate
         prevChild = newParentsChildNames[parent]
         update_child!(graph, parent, prevChild, Symbol(to_var_name(n1.id)))
     end